The present invention relates to microfabricated fluidic systems and methods for regulating the flow of fluid to provide switches, logic gates, latches, pressure sources, analog devices, capacitors, unidirectional valves, pressure multipliers, and devices that perform mathematical functions.
Microfabricated fluidic chips may be used for biological assays. For example, microfabricated fluidic chips may be used to perform biological assays using external control lines that control the opening and closing of on-chip fluidic valves. The on-chip fluidic valves control the flow of fluids in biological assays. The valves are opened and closed using macroscopic pressure sources that are located off-chip, and which are connected through control lines to the chip. In complex assays, a large number of macroscopic control lines is cumbersome and undesirable. Previously known electrical actuating devices have not been able to provide sufficient force by themselves to open or close a fluidic valve.
It would therefore be desirable to provide pressure sources and control lines on-chip that control the opening and closing of on-chip valves so that macroscopic control lines exiting the chip are minimized or eliminated. Previously known on-chip systems have not been adequate to provide control of numerous on-chip valves. Each valve requires a pressure differential between the input and the output to control the valve. Numerous valves coupled together to perform complex functions would require very large pressure differentials to drive all of the cascaded valves. Pressure sources that generate such very high pressure differentials are difficult to manufacture on a microfabricated chip.
Furthermore, such cascaded valve systems do not allow for the introduction of feedback elements. A feedback element is one whereby a (downstream) output pressure, which is controlled by an upstream valve or is controlled by a valve which is controlled by the upstream valve (and so on), in turn controls the function of the upstream valve. The elimination of the possibility of feedback precludes the construction of entire classes of analog devices and digital logic devices (e.g., latches).
It would also be desirable to provide numerous microfabricated fluidic switches on-chip that open and close channels without the need for large pressure differentials.
It would also be desirable to provide devices that perform logic functions, signal latching, mathematical functions, and other complex functions on-chip.
It would also be desirable to provide microfabricated fluidic switches on-chip that incorporate the feed back of information from a downstream part of the circuit to an upstream part.